The Protégé platform supports two main ways of modelling ontologies - frame-based and OWL,
each with its own user interface. Please refer to the
Overview section
of our Web site for more information on the differences between the
Protégé-Frames and
Protégé-OWL editors.
This page is intended to be a quick start guide, focused on Protégé's OWL support.
You will learn how to open OWL files and begin interacting with the Protégé-OWL user interface.
For a more in-depth discussion of features, please see the
Protégé-OWL tutorial.
If you are interested in frame-based ontology development instead, please see the
Getting Started with Protégé-Frames
tutorial.
- Verify that Protégé-OWL is properly installed
- Creating and loading projects
- Understanding projects in Protégé
- Open an example OWL project
- Creating an empty OWL project
- Open an existing OWL project
- Open an OWL file without an existing project
- Saving projects
- Where do I go next?
01. Verify that Protégé-OWL is properly installed
The Protégé-OWL editor is bundled with the "full" installation of the Protégé
platform. During the install process, choose the "Basic + OWL" option. This will install the
Core Protégé system, the Protégé-OWL editor, and
only those plug-ins that are compatible with OWL ontologies.
When you create new projects in Protege-OWL, there should be two project types in the Create New Project
dialog: "OWL/RDF Files" and "OWL/RDF Database". If neither of those project types appear,
it means that OWL support was not correctly installed. If this is the case, please do the following:
- Check that your Protégé installation directory contains a subfolder
called
/plugins/edu.stanford.smi.protegex.owl/
and that this directory
has some contents (JAR files and other things).
- If you cannot get OWL files to load, try re-installing Protégé and make sure you select
"Basic + OWL" during the install process.
02. Creating and Loading Projects
If you just wish to browse the Protégé-OWL user interface, the "pizza.owl" example
OWL file is a useful place to start. It comes with the default installation and can be found in the
directory:
<protege-install-dir>/examples/pizza/pizza.owl
. Alternatively, you may want to
create a new empty project and begin modeling right away, or open an existing ontology.
02.a Understanding Projects in Protégé
When you start Protégé, you are presented with the "Welcome to Protégé"
dialog. From here you can create new projects, open existing projects, or launch help topics.

When you use Protégé to create and edit ontologies you will generate at least 2 files:
- A project file (with the extension .pprj). The project file stores information
relating to any interface customizations or editor options you have selected. In many cases you will not
need to send this file to colleagues with your ontology unless you have been customizing forms with the
Forms Tab. Project files created with older versions of Protégé-OWL (especially prior to
version 3.0) may not be compatible with your current version, in which case you may need to build a
new project from scratch.
- A source file (with the extensions .owl, .rdfs, or .rdf). This file is where your ontology
classes, individuals and properties are defined. There may be several source files depending on how the
ontology has been defined. If it is modular and has been created properly, Protégé-OWL will
find and load all of the appropriate source files.
02.b Open an example OWL project
From the welcome dialog:
- Double-click
pizza.owl
in the Recently Accessed
pane.
- The example pizza ontology should now load into the Protégé-OWL editing environment.
If the welcome dialog has already been dismissed:
- Select
File | Open Recent
.
- Several recently opened files should be listed
including
pizza.owl.pprj
.
02.c Creating an empty OWL project
From the welcome dialog:
- Select "Create New Project..."
- The Create New Project wizard appears:

- Select
OWL/RDF Files
and click Next >.
- Specify a unique URI, which will become the identifier for your ontology. Typically, the URI should represent the
location where you will publish your ontology, but this is not a firm requirement. Setting a unique URI for you ontology
during the creation process can help prevent problems later on when doing imports of other ontologies.

Click Next >.
- Select which OWL/RDF dialect you would like to use. Selecting a particular dialect will enable or disable
certain features in the Protégé-OWL user interface, so that your ontology more closely fits your
target language profile.

- At this point, you can either click Finish to create an empty OWL project, or you can advance to the last page
of the Wizard to choose the initial user interface setting for the OWLClasses tab.

The Logic View is very expressive but is not very intuitive for OWL beginners. The Properties View provides
a simpler user interface that is more appropriate for beginners.
- Click Finish. An empty project is created and you are ready to start editing your ontology.
If the welcome dialog has already been dismissed:
- Select File | New Project...
- Save your current project if necessary.
- The same wizard as above is now shown.
02.d Open an existing OWL project
From the desktop (in Windows):
- Double-click on the .pprj file.
- Protégé should be associated with this file extension, will start automatically, and your
project will be loaded.
From within Protégé:
- Select Open Existing File... from the welcome dialog or File | Open... if the welcome dialog has
already been dismissed.
- Locate your project (.pprj) file in the Open Project dialog and click OK.
02.e Open an OWL file without an existing project
If all you have is an OWL source file, you will need to create a new project to load it into
Protégé.
From the welcome dialog:
- Click the Create New Project... button to launch the Create New Project wizard.
- Make sure OWL/RDF Files is selected as the project type.
- Tick the Create from Existing Sources checkbox.
- Click Next > to specifiy the location of your source file.

- A local OWL file can be specified by opening a file chooser dialog with the box+ button, or the URL
of a remote ontology can be entered, e.g.,
http://www.co-ode.org/ontologies/pizza/2005/10/18/pizza.owl.
- Click Next > to specify your target language profile, and then click Finish to load your existing OWL file into
a new Protégé-OWL project.
If the welcome dialog has already been dismissed:
- Select File | New Project...
- Save your current project if necessary.
- The same wizard as above is now shown - follow steps 2-6.
03. Saving projects
Saving projects in Protégé-OWL is simple. Select "Save Project" or "Save Project As..." from the File menu.
In the resulting dialog, make sure you specify a name and location for your project in Project field.
By default, the name of the OWL source file will match your project name and will be saved in the same directory
as your project file (unless you specify otherwise in the "OWL File name or URL" field).
04. Where do I go next?